Yong Xin, Du Ke
Department of Mechanical Engineering, Binghamton University, Binghamton, New York 13902, United States.
Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92521, United States.
J Phys Chem B. 2023 Feb 23;127(7):1652-1663. doi: 10.1021/acs.jpcb.2c07460. Epub 2023 Feb 10.
Cellular uptake of nanoplastics is instrumental in their environmental accumulation and transfer to humans through the food chain. Despite extensive studies using spherical plastic nanoparticles, the influence of the morphological characteristics of environmentally released nanoplastics is understudied. Using dissipative particle dynamics simulations, we modeled the interactions between a cell membrane and hydrophobic nanotetrahedra, which feature high shape anisotropy and large surface curvature seen for environmental nanoplastics. We observe robust uptake of nanotetrahedra with sharp vertices and edges by the lipid membrane. Two local energy minimum configurations of nanotetrahedra embedded in the membrane bilayer were identified for particles of large sizes. Further analysis of particle dynamics within the membrane shows that the two interaction states exhibit distinct translational and rotational dynamics in the directions normal and parallel to the plane of the membrane. The membrane confinement significantly arrests the out-of-plane motion, resulting in caged translation and subdiffusive rotation. While the in-plane diffusion remains Brownian, we find that the translational and rotational modes decouple from each other as the particle size increases. The rotational diffusion decreases by a greater extent compared to the translational diffusion, deviating from the continuum theory predictions. These results provide fundamental insights into the shape effect on the nanoparticle dynamics in crowded lipid membranes.
纳米塑料的细胞摄取在其环境积累以及通过食物链向人类的转移过程中起着重要作用。尽管已经对球形塑料纳米颗粒进行了广泛研究，但环境中释放的纳米塑料的形态特征的影响仍未得到充分研究。我们使用耗散粒子动力学模拟，对细胞膜与疏水性纳米四面体之间的相互作用进行了建模，这种纳米四面体具有高形状各向异性和环境纳米塑料所具有的大表面曲率。我们观察到脂质膜对具有尖锐顶点和边缘的纳米四面体有很强的摄取作用。对于大尺寸的颗粒，确定了嵌入膜双层中的纳米四面体的两种局部能量最小构型。对膜内颗粒动力学的进一步分析表明，这两种相互作用状态在垂直和平行于膜平面的方向上表现出不同的平移和旋转动力学。膜的限制显著抑制了平面外运动，导致笼状平移和亚扩散旋转。虽然平面内扩散仍然是布朗运动，但我们发现随着颗粒尺寸的增加，平移和旋转模式相互解耦。与平移扩散相比，旋转扩散下降的幅度更大，这与连续介质理论预测不同。这些结果为拥挤脂质膜中纳米颗粒动力学的形状效应提供了基本见解。
